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lift_ι (W : C) (k : Π a, W ⟶ I.left a) (h : ∀ b, k (I.fst_to b) ≫ I.fst b = k (I.snd_to b) ≫ I.snd b) (a) : multiequalizer.lift I _ k h ≫ multiequalizer.ι I a = k _
limit.lift_π _ _
lemma
category_theory.limits.multiequalizer.lift_ι
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_ext {W : C} (i j : W ⟶ multiequalizer I) (h : ∀ a, i ≫ multiequalizer.ι I a = j ≫ multiequalizer.ι I a) : i = j
limit.hom_ext begin rintro (a|b), { apply h }, simp_rw [← limit.w I.multicospan (walking_multicospan.hom.fst b), ← category.assoc, h], end
lemma
category_theory.limits.multiequalizer.hom_ext
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[ "hom_ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_equalizer : multiequalizer I ≅ equalizer I.fst_pi_map I.snd_pi_map
limit.iso_limit_cone ⟨_, is_limit.of_preserves_cone_terminal I.multifork_equiv_pi_fork.inverse (limit.is_limit _)⟩
def
category_theory.limits.multiequalizer.iso_equalizer
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
The multiequalizer is isomorphic to the equalizer of `∏ I.left ⇉ ∏ I.right`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ι_pi : multiequalizer I ⟶ ∏ I.left
(iso_equalizer I).hom ≫ equalizer.ι I.fst_pi_map I.snd_pi_map
def
category_theory.limits.multiequalizer.ι_pi
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
The canonical injection `multiequalizer I ⟶ ∏ I.left`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ι_pi_π (a) : ι_pi I ≫ pi.π I.left a = ι I a
by { rw [ι_pi, category.assoc, ← iso.eq_inv_comp, iso_equalizer], simpa }
lemma
category_theory.limits.multiequalizer.ι_pi_π
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
π (b : I.R) : I.right b ⟶ multicoequalizer I
colimit.ι I.multispan (walking_multispan.right _)
abbreviation
category_theory.limits.multicoequalizer.π
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
The canonical map from the multiequalizer to the objects on the left.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
multicofork : multicofork I
colimit.cocone _
abbreviation
category_theory.limits.multicoequalizer.multicofork
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
The multicofork associated to the multicoequalizer.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
multicofork_π (b) : (multicoequalizer.multicofork I).π b = multicoequalizer.π I b
rfl
lemma
category_theory.limits.multicoequalizer.multicofork_π
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
multicofork_ι_app_right (b) : (multicoequalizer.multicofork I).ι.app (walking_multispan.right b) = multicoequalizer.π I b
rfl
lemma
category_theory.limits.multicoequalizer.multicofork_ι_app_right
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
condition (a) : I.fst a ≫ multicoequalizer.π I (I.fst_from a) = I.snd a ≫ multicoequalizer.π I (I.snd_from a)
multicofork.condition _ _
lemma
category_theory.limits.multicoequalizer.condition
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc (W : C) (k : Π b, I.right b ⟶ W) (h : ∀ a, I.fst a ≫ k (I.fst_from a) = I.snd a ≫ k (I.snd_from a)) : multicoequalizer I ⟶ W
colimit.desc _ (multicofork.of_π I _ k h)
abbreviation
category_theory.limits.multicoequalizer.desc
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
Construct a morphism from the multicoequalizer from its universal property.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
π_desc (W : C) (k : Π b, I.right b ⟶ W) (h : ∀ a, I.fst a ≫ k (I.fst_from a) = I.snd a ≫ k (I.snd_from a)) (b) : multicoequalizer.π I b ≫ multicoequalizer.desc I _ k h = k _
colimit.ι_desc _ _
lemma
category_theory.limits.multicoequalizer.π_desc
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_ext {W : C} (i j : multicoequalizer I ⟶ W) (h : ∀ b, multicoequalizer.π I b ≫ i = multicoequalizer.π I b ≫ j) : i = j
colimit.hom_ext begin rintro (a|b), { simp_rw [← colimit.w I.multispan (walking_multispan.hom.fst a), category.assoc, h] }, { apply h }, end
lemma
category_theory.limits.multicoequalizer.hom_ext
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[ "hom_ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_coequalizer : multicoequalizer I ≅ coequalizer I.fst_sigma_map I.snd_sigma_map
colimit.iso_colimit_cocone ⟨_, is_colimit.of_preserves_cocone_initial I.multicofork_equiv_sigma_cofork.inverse (colimit.is_colimit _)⟩
def
category_theory.limits.multicoequalizer.iso_coequalizer
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
The multicoequalizer is isomorphic to the coequalizer of `∐ I.left ⇉ ∐ I.right`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_π : ∐ I.right ⟶ multicoequalizer I
coequalizer.π I.fst_sigma_map I.snd_sigma_map ≫ (iso_coequalizer I).inv
def
category_theory.limits.multicoequalizer.sigma_π
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
The canonical projection `∐ I.right ⟶ multicoequalizer I`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ι_sigma_π (b) : sigma.ι I.right b ≫ sigma_π I = π I b
by { rw [sigma_π, ← category.assoc, iso.comp_inv_eq, iso_coequalizer], simpa }
lemma
category_theory.limits.multicoequalizer.ι_sigma_π
category_theory.limits.shapes
src/category_theory/limits/shapes/multiequalizer.lean
[ "category_theory.limits.shapes.products", "category_theory.limits.shapes.equalizers", "category_theory.limits.cone_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fan (f : β → C)
cone (discrete.functor f)
abbreviation
category_theory.limits.fan
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
A fan over `f : β → C` consists of a collection of maps from an object `P` to every `f b`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cofan (f : β → C)
cocone (discrete.functor f)
abbreviation
category_theory.limits.cofan
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
A cofan over `f : β → C` consists of a collection of maps from every `f b` to an object `P`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fan.mk {f : β → C} (P : C) (p : Π b, P ⟶ f b) : fan f
{ X := P, π := { app := λ X, p X.as } }
def
category_theory.limits.fan.mk
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
A fan over `f : β → C` consists of a collection of maps from an object `P` to every `f b`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cofan.mk {f : β → C} (P : C) (p : Π b, f b ⟶ P) : cofan f
{ X := P, ι := { app := λ X, p X.as } }
def
category_theory.limits.cofan.mk
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
A cofan over `f : β → C` consists of a collection of maps from every `f b` to an object `P`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fan.proj {f : β → C} (p : fan f) (j : β) : p.X ⟶ f j
p.π.app (discrete.mk j)
def
category_theory.limits.fan.proj
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
Get the `j`th map in the fan
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fan_mk_proj {f : β → C} (P : C) (p : Π b, P ⟶ f b) (j : β) : (fan.mk P p).proj j = p j
rfl
lemma
category_theory.limits.fan_mk_proj
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_product (f : β → C)
has_limit (discrete.functor f)
abbreviation
category_theory.limits.has_product
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
An abbreviation for `has_limit (discrete.functor f)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_coproduct (f : β → C)
has_colimit (discrete.functor f)
abbreviation
category_theory.limits.has_coproduct
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
An abbreviation for `has_colimit (discrete.functor f)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_fan_limit {f : β → C} (t : fan f) (lift : Π s : fan f, s.X ⟶ t.X) (fac : ∀ (s : fan f) (j : β), lift s ≫ (t.proj j) = s.proj j) (uniq : ∀ (s : fan f) (m : s.X ⟶ t.X) (w : ∀ j : β, m ≫ t.proj j = s.proj j), m = lift s) : is_limit t
{ lift := lift, fac' := λ s j, by convert fac s j.as; simp, uniq' := λ s m w, uniq s m (λ j, w (discrete.mk j)), }
def
category_theory.limits.mk_fan_limit
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[ "lift" ]
Make a fan `f` into a limit fan by providing `lift`, `fac`, and `uniq` -- just a convenience lemma to avoid having to go through `discrete`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_products_of_shape (β : Type v)
has_limits_of_shape.{v} (discrete β)
abbreviation
category_theory.limits.has_products_of_shape
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
An abbreviation for `has_limits_of_shape (discrete f)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_coproducts_of_shape (β : Type v)
has_colimits_of_shape.{v} (discrete β)
abbreviation
category_theory.limits.has_coproducts_of_shape
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
An abbreviation for `has_colimits_of_shape (discrete f)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pi_obj (f : β → C) [has_product f]
limit (discrete.functor f)
abbreviation
category_theory.limits.pi_obj
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
`pi_obj f` computes the product of a family of elements `f`. (It is defined as an abbreviation for `limit (discrete.functor f)`, so for most facts about `pi_obj f`, you will just use general facts about limits.)
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_obj (f : β → C) [has_coproduct f]
colimit (discrete.functor f)
abbreviation
category_theory.limits.sigma_obj
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
`sigma_obj f` computes the coproduct of a family of elements `f`. (It is defined as an abbreviation for `colimit (discrete.functor f)`, so for most facts about `sigma_obj f`, you will just use general facts about colimits.)
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pi.π (f : β → C) [has_product f] (b : β) : ∏ f ⟶ f b
limit.π (discrete.functor f) (discrete.mk b)
abbreviation
category_theory.limits.pi.π
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
The `b`-th projection from the pi object over `f` has the form `∏ f ⟶ f b`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma.ι (f : β → C) [has_coproduct f] (b : β) : f b ⟶ ∐ f
colimit.ι (discrete.functor f) (discrete.mk b)
abbreviation
category_theory.limits.sigma.ι
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
The `b`-th inclusion into the sigma object over `f` has the form `f b ⟶ ∐ f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
product_is_product (f : β → C) [has_product f] : is_limit (fan.mk _ (pi.π f))
is_limit.of_iso_limit (limit.is_limit (discrete.functor f)) (cones.ext (iso.refl _) (by tidy))
def
category_theory.limits.product_is_product
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
The fan constructed of the projections from the product is limiting.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coproduct_is_coproduct (f : β → C) [has_coproduct f] : is_colimit (cofan.mk _ (sigma.ι f))
is_colimit.of_iso_colimit (colimit.is_colimit (discrete.functor f)) (cocones.ext (iso.refl _) (by tidy))
def
category_theory.limits.coproduct_is_coproduct
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
The cofan constructed of the inclusions from the coproduct is colimiting.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pi.lift {f : β → C} [has_product f] {P : C} (p : Π b, P ⟶ f b) : P ⟶ ∏ f
limit.lift _ (fan.mk P p)
abbreviation
category_theory.limits.pi.lift
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
A collection of morphisms `P ⟶ f b` induces a morphism `P ⟶ ∏ f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma.desc {f : β → C} [has_coproduct f] {P : C} (p : Π b, f b ⟶ P) : ∐ f ⟶ P
colimit.desc _ (cofan.mk P p)
abbreviation
category_theory.limits.sigma.desc
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
A collection of morphisms `f b ⟶ P` induces a morphism `∐ f ⟶ P`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pi.map {f g : β → C} [has_product f] [has_product g] (p : Π b, f b ⟶ g b) : ∏ f ⟶ ∏ g
lim_map (discrete.nat_trans (λ X, p X.as))
abbreviation
category_theory.limits.pi.map
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
Construct a morphism between categorical products (indexed by the same type) from a family of morphisms between the factors.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pi.map_mono {f g : β → C} [has_product f] [has_product g] (p : Π b, f b ⟶ g b) [Π i, mono (p i)] : mono $ pi.map p
@@limits.lim_map_mono _ _ _ _ _ (by { dsimp, apply_instance })
instance
category_theory.limits.pi.map_mono
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pi.map_iso {f g : β → C} [has_products_of_shape β C] (p : Π b, f b ≅ g b) : ∏ f ≅ ∏ g
lim.map_iso (discrete.nat_iso (λ X, p X.as))
abbreviation
category_theory.limits.pi.map_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
Construct an isomorphism between categorical products (indexed by the same type) from a family of isomorphisms between the factors.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma.map {f g : β → C} [has_coproduct f] [has_coproduct g] (p : Π b, f b ⟶ g b) : ∐ f ⟶ ∐ g
colim_map (discrete.nat_trans (λ X, p X.as))
abbreviation
category_theory.limits.sigma.map
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[ "sigma.map" ]
Construct a morphism between categorical coproducts (indexed by the same type) from a family of morphisms between the factors.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma.map_epi {f g : β → C} [has_coproduct f] [has_coproduct g] (p : Π b, f b ⟶ g b) [Π i, epi (p i)] : epi $ sigma.map p
@@limits.colim_map_epi _ _ _ _ _ (by { dsimp, apply_instance })
instance
category_theory.limits.sigma.map_epi
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[ "sigma.map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma.map_iso {f g : β → C} [has_coproducts_of_shape β C] (p : Π b, f b ≅ g b) : ∐ f ≅ ∐ g
colim.map_iso (discrete.nat_iso (λ X, p X.as))
abbreviation
category_theory.limits.sigma.map_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
Construct an isomorphism between categorical coproducts (indexed by the same type) from a family of isomorphisms between the factors.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pi_comparison [has_product f] [has_product (λ b, G.obj (f b))] : G.obj (∏ f) ⟶ ∏ (λ b, G.obj (f b))
pi.lift (λ b, G.map (pi.π f b))
def
category_theory.limits.pi_comparison
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
The comparison morphism for the product of `f`. This is an iso iff `G` preserves the product of `f`, see `preserves_product.of_iso_comparison`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pi_comparison_comp_π [has_product f] [has_product (λ b, G.obj (f b))] (b : β) : pi_comparison G f ≫ pi.π _ b = G.map (pi.π f b)
limit.lift_π _ (discrete.mk b)
lemma
category_theory.limits.pi_comparison_comp_π
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_lift_pi_comparison [has_product f] [has_product (λ b, G.obj (f b))] (P : C) (g : Π j, P ⟶ f j) : G.map (pi.lift g) ≫ pi_comparison G f = pi.lift (λ j, G.map (g j))
by { ext, discrete_cases, simp [← G.map_comp] }
lemma
category_theory.limits.map_lift_pi_comparison
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_comparison [has_coproduct f] [has_coproduct (λ b, G.obj (f b))] : ∐ (λ b, G.obj (f b)) ⟶ G.obj (∐ f)
sigma.desc (λ b, G.map (sigma.ι f b))
def
category_theory.limits.sigma_comparison
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
The comparison morphism for the coproduct of `f`. This is an iso iff `G` preserves the coproduct of `f`, see `preserves_coproduct.of_iso_comparison`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ι_comp_sigma_comparison [has_coproduct f] [has_coproduct (λ b, G.obj (f b))] (b : β) : sigma.ι _ b ≫ sigma_comparison G f = G.map (sigma.ι f b)
colimit.ι_desc _ (discrete.mk b)
lemma
category_theory.limits.ι_comp_sigma_comparison
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma_comparison_map_desc [has_coproduct f] [has_coproduct (λ b, G.obj (f b))] (P : C) (g : Π j, f j ⟶ P) : sigma_comparison G f ≫ G.map (sigma.desc g) = sigma.desc (λ j, G.map (g j))
by { ext, discrete_cases, simp [← G.map_comp] }
lemma
category_theory.limits.sigma_comparison_map_desc
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_products
Π (J : Type w), has_limits_of_shape (discrete J) C
abbreviation
category_theory.limits.has_products
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
An abbreviation for `Π J, has_limits_of_shape (discrete J) C`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_coproducts
Π (J : Type w), has_colimits_of_shape (discrete J) C
abbreviation
category_theory.limits.has_coproducts
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
An abbreviation for `Π J, has_colimits_of_shape (discrete J) C`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_smallest_products_of_has_products [has_products.{w} C] : has_products.{0} C
λ J, has_limits_of_shape_of_equivalence (discrete.equivalence equiv.ulift : discrete (ulift.{w} J) ≌ _)
lemma
category_theory.limits.has_smallest_products_of_has_products
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[ "equiv.ulift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_smallest_coproducts_of_has_coproducts [has_coproducts.{w} C] : has_coproducts.{0} C
λ J, has_colimits_of_shape_of_equivalence (discrete.equivalence equiv.ulift : discrete (ulift.{w} J) ≌ _)
lemma
category_theory.limits.has_smallest_coproducts_of_has_coproducts
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[ "equiv.ulift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_products_of_limit_fans (lf : ∀ {J : Type w} (f : J → C), fan f) (lf_is_limit : ∀ {J : Type w} (f : J → C), is_limit (lf f)) : has_products.{w} C
λ (J : Type w), { has_limit := λ F, has_limit.mk ⟨(cones.postcompose discrete.nat_iso_functor.inv).obj (lf (λ j, F.obj ⟨j⟩)), (is_limit.postcompose_inv_equiv _ _).symm (lf_is_limit _)⟩ }
lemma
category_theory.limits.has_products_of_limit_fans
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
limit_cone_of_unique : limit_cone (discrete.functor f)
{ cone := { X := f default, π := { app := λ j, eq_to_hom (by { dsimp, congr, }), }, }, is_limit := { lift := λ s, s.π.app default, fac' := λ s j, begin have w := (s.π.naturality (eq_to_hom (unique.default_eq _))).symm, dsimp at w, simpa [eq_to_hom_map] using w, end, uniq' := λ s ...
def
category_theory.limits.limit_cone_of_unique
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[ "lift", "unique.default_eq" ]
The limit cone for the product over an index type with exactly one term.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_product_unique : has_product f
has_limit.mk (limit_cone_of_unique f)
instance
category_theory.limits.has_product_unique
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
product_unique_iso : ∏ f ≅ f default
is_limit.cone_point_unique_up_to_iso (limit.is_limit _) (limit_cone_of_unique f).is_limit
def
category_theory.limits.product_unique_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
A product over a index type with exactly one term is just the object over that term.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
colimit_cocone_of_unique : colimit_cocone (discrete.functor f)
{ cocone := { X := f default, ι := { app := λ j, eq_to_hom (by { discrete_cases, dsimp, congr, }), }, }, is_colimit := { desc := λ s, s.ι.app default, fac' := λ s j, begin have w := (s.ι.naturality (eq_to_hom (unique.eq_default _))), dsimp at w, simpa [eq_to_hom_map] using w, end, ...
def
category_theory.limits.colimit_cocone_of_unique
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[ "unique.eq_default" ]
The colimit cocone for the coproduct over an index type with exactly one term.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_coproduct_unique : has_coproduct f
has_colimit.mk (colimit_cocone_of_unique f)
instance
category_theory.limits.has_coproduct_unique
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coproduct_unique_iso : ∐ f ≅ f default
is_colimit.cocone_point_unique_up_to_iso (colimit.is_colimit _) (colimit_cocone_of_unique f).is_colimit
def
category_theory.limits.coproduct_unique_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
A coproduct over a index type with exactly one term is just the object over that term.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pi.reindex : pi_obj (f ∘ ε) ≅ pi_obj f
has_limit.iso_of_equivalence (discrete.equivalence ε) (discrete.nat_iso (λ i, iso.refl _))
def
category_theory.limits.pi.reindex
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
Reindex a categorical product via an equivalence of the index types.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pi.reindex_hom_π (b : β) : (pi.reindex ε f).hom ≫ pi.π f (ε b) = pi.π (f ∘ ε) b
begin dsimp [pi.reindex], simp only [has_limit.iso_of_equivalence_hom_π, discrete.nat_iso_inv_app, equivalence.equivalence_mk'_counit, discrete.equivalence_counit_iso, discrete.nat_iso_hom_app, eq_to_iso.hom, eq_to_hom_map], dsimp, simpa [eq_to_hom_map] using limit.w (discrete.functor (f ∘ ε)) (disc...
lemma
category_theory.limits.pi.reindex_hom_π
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pi.reindex_inv_π (b : β) : (pi.reindex ε f).inv ≫ pi.π (f ∘ ε) b = pi.π f (ε b)
by simp [iso.inv_comp_eq]
lemma
category_theory.limits.pi.reindex_inv_π
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma.reindex : sigma_obj (f ∘ ε) ≅ sigma_obj f
has_colimit.iso_of_equivalence (discrete.equivalence ε) (discrete.nat_iso (λ i, iso.refl _))
def
category_theory.limits.sigma.reindex
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
Reindex a categorical coproduct via an equivalence of the index types.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma.ι_reindex_hom (b : β) : sigma.ι (f ∘ ε) b ≫ (sigma.reindex ε f).hom = sigma.ι f (ε b)
begin dsimp [sigma.reindex], simp only [has_colimit.iso_of_equivalence_hom_π, equivalence.equivalence_mk'_unit, discrete.equivalence_unit_iso, discrete.nat_iso_hom_app, eq_to_iso.hom, eq_to_hom_map, discrete.nat_iso_inv_app], dsimp, simp [eq_to_hom_map, ←colimit.w (discrete.functor f) (discrete.eq_t...
lemma
category_theory.limits.sigma.ι_reindex_hom
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sigma.ι_reindex_inv (b : β) : sigma.ι f (ε b) ≫ (sigma.reindex ε f).inv = sigma.ι (f ∘ ε) b
by simp [iso.comp_inv_eq]
lemma
category_theory.limits.sigma.ι_reindex_inv
category_theory.limits.shapes
src/category_theory/limits/shapes/products.lean
[ "category_theory.limits.has_limits", "category_theory.discrete_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_cospan : Type
wide_pullback_shape walking_pair
abbreviation
category_theory.limits.walking_cospan
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The type of objects for the diagram indexing a pullback, defined as a special case of `wide_pullback_shape`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_cospan.left : walking_cospan
some walking_pair.left
abbreviation
category_theory.limits.walking_cospan.left
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The left point of the walking cospan.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_cospan.right : walking_cospan
some walking_pair.right
abbreviation
category_theory.limits.walking_cospan.right
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The right point of the walking cospan.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_cospan.one : walking_cospan
none
abbreviation
category_theory.limits.walking_cospan.one
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The central point of the walking cospan.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_span : Type
wide_pushout_shape walking_pair
abbreviation
category_theory.limits.walking_span
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The type of objects for the diagram indexing a pushout, defined as a special case of `wide_pushout_shape`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_span.left : walking_span
some walking_pair.left
abbreviation
category_theory.limits.walking_span.left
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The left point of the walking span.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_span.right : walking_span
some walking_pair.right
abbreviation
category_theory.limits.walking_span.right
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The right point of the walking span.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_span.zero : walking_span
none
abbreviation
category_theory.limits.walking_span.zero
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The central point of the walking span.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom : walking_cospan → walking_cospan → Type
wide_pullback_shape.hom
abbreviation
category_theory.limits.walking_cospan.hom
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The type of arrows for the diagram indexing a pullback.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom.inl : left ⟶ one
wide_pullback_shape.hom.term _
abbreviation
category_theory.limits.walking_cospan.hom.inl
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The left arrow of the walking cospan.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom.inr : right ⟶ one
wide_pullback_shape.hom.term _
abbreviation
category_theory.limits.walking_cospan.hom.inr
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The right arrow of the walking cospan.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom.id (X : walking_cospan) : X ⟶ X
wide_pullback_shape.hom.id X
abbreviation
category_theory.limits.walking_cospan.hom.id
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The identity arrows of the walking cospan.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom : walking_span → walking_span → Type
wide_pushout_shape.hom
abbreviation
category_theory.limits.walking_span.hom
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The type of arrows for the diagram indexing a pushout.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom.fst : zero ⟶ left
wide_pushout_shape.hom.init _
abbreviation
category_theory.limits.walking_span.hom.fst
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The left arrow of the walking span.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom.snd : zero ⟶ right
wide_pushout_shape.hom.init _
abbreviation
category_theory.limits.walking_span.hom.snd
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The right arrow of the walking span.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom.id (X : walking_span) : X ⟶ X
wide_pushout_shape.hom.id X
abbreviation
category_theory.limits.walking_span.hom.id
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The identity arrows of the walking span.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_cospan.ext {F : walking_cospan ⥤ C} {s t : cone F} (i : s.X ≅ t.X) (w₁ : s.π.app walking_cospan.left = i.hom ≫ t.π.app walking_cospan.left) (w₂ : s.π.app walking_cospan.right = i.hom ≫ t.π.app walking_cospan.right) : s ≅ t
begin apply cones.ext i, rintro (⟨⟩|⟨⟨⟩⟩), { have h₁ := s.π.naturality walking_cospan.hom.inl, dsimp at h₁, simp only [category.id_comp] at h₁, have h₂ := t.π.naturality walking_cospan.hom.inl, dsimp at h₂, simp only [category.id_comp] at h₂, simp_rw [h₂, ←category.assoc, ←w₁, ←h₁], }, { exact w...
def
category_theory.limits.walking_cospan.ext
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
To construct an isomorphism of cones over the walking cospan, it suffices to construct an isomorphism of the cone points and check it commutes with the legs to `left` and `right`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_span.ext {F : walking_span ⥤ C} {s t : cocone F} (i : s.X ≅ t.X) (w₁ : s.ι.app walking_cospan.left ≫ i.hom = t.ι.app walking_cospan.left) (w₂ : s.ι.app walking_cospan.right ≫ i.hom = t.ι.app walking_cospan.right) : s ≅ t
begin apply cocones.ext i, rintro (⟨⟩|⟨⟨⟩⟩), { have h₁ := s.ι.naturality walking_span.hom.fst, dsimp at h₁, simp only [category.comp_id] at h₁, have h₂ := t.ι.naturality walking_span.hom.fst, dsimp at h₂, simp only [category.comp_id] at h₂, simp_rw [←h₁, category.assoc, w₁, h₂], }, { exact w₁, }...
def
category_theory.limits.walking_span.ext
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
To construct an isomorphism of cocones over the walking span, it suffices to construct an isomorphism of the cocone points and check it commutes with the legs from `left` and `right`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cospan {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) : walking_cospan ⥤ C
wide_pullback_shape.wide_cospan Z (λ j, walking_pair.cases_on j X Y) (λ j, walking_pair.cases_on j f g)
def
category_theory.limits.cospan
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
`cospan f g` is the functor from the walking cospan hitting `f` and `g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
span {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) : walking_span ⥤ C
wide_pushout_shape.wide_span X (λ j, walking_pair.cases_on j Y Z) (λ j, walking_pair.cases_on j f g)
def
category_theory.limits.span
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
`span f g` is the functor from the walking span hitting `f` and `g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cospan_left {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) : (cospan f g).obj walking_cospan.left = X
rfl
lemma
category_theory.limits.cospan_left
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
span_left {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) : (span f g).obj walking_span.left = Y
rfl
lemma
category_theory.limits.span_left
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cospan_right {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) : (cospan f g).obj walking_cospan.right = Y
rfl
lemma
category_theory.limits.cospan_right
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
span_right {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) : (span f g).obj walking_span.right = Z
rfl
lemma
category_theory.limits.span_right
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cospan_one {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) : (cospan f g).obj walking_cospan.one = Z
rfl
lemma
category_theory.limits.cospan_one
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
span_zero {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) : (span f g).obj walking_span.zero = X
rfl
lemma
category_theory.limits.span_zero
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cospan_map_inl {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) : (cospan f g).map walking_cospan.hom.inl = f
rfl
lemma
category_theory.limits.cospan_map_inl
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
span_map_fst {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) : (span f g).map walking_span.hom.fst = f
rfl
lemma
category_theory.limits.span_map_fst
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cospan_map_inr {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) : (cospan f g).map walking_cospan.hom.inr = g
rfl
lemma
category_theory.limits.cospan_map_inr
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
span_map_snd {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) : (span f g).map walking_span.hom.snd = g
rfl
lemma
category_theory.limits.span_map_snd
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cospan_map_id {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) (w : walking_cospan) : (cospan f g).map (walking_cospan.hom.id w) = 𝟙 _
rfl
lemma
category_theory.limits.cospan_map_id
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
span_map_id {X Y Z : C} (f : X ⟶ Y) (g : X ⟶ Z) (w : walking_span) : (span f g).map (walking_span.hom.id w) = 𝟙 _
rfl
lemma
category_theory.limits.span_map_id
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diagram_iso_cospan (F : walking_cospan ⥤ C) : F ≅ cospan (F.map inl) (F.map inr)
nat_iso.of_components (λ j, eq_to_iso (by tidy)) (by tidy)
def
category_theory.limits.diagram_iso_cospan
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
Every diagram indexing an pullback is naturally isomorphic (actually, equal) to a `cospan`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diagram_iso_span (F : walking_span ⥤ C) : F ≅ span (F.map fst) (F.map snd)
nat_iso.of_components (λ j, eq_to_iso (by tidy)) (by tidy)
def
category_theory.limits.diagram_iso_span
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
Every diagram indexing a pushout is naturally isomorphic (actually, equal) to a `span`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cospan_comp_iso (F : C ⥤ D) {X Y Z : C} (f : X ⟶ Z) (g : Y ⟶ Z) : cospan f g ⋙ F ≅ cospan (F.map f) (F.map g)
nat_iso.of_components (by rintros (⟨⟩|⟨⟨⟩⟩); exact iso.refl _) (by rintros (⟨⟩|⟨⟨⟩⟩) (⟨⟩|⟨⟨⟩⟩) ⟨⟩; repeat { dsimp, simp, })
def
category_theory.limits.cospan_comp_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
A functor applied to a cospan is a cospan.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cospan_comp_iso_app_left : (cospan_comp_iso F f g).app walking_cospan.left = iso.refl _
rfl
lemma
category_theory.limits.cospan_comp_iso_app_left
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83